The ratio of the number of tarts to the number of shortbreads in a supermarket is 3 : 1. A tart costs $1.10 and a shortbread costs $0.70. If all the tarts and shortbreads are sold, a sum of $40 will be collected. How many tarts are there altogether?
| |
Tarts |
Shortbreads |
Total |
| Number |
3 u |
1 u |
|
| Value |
$1.10 |
$0.70 |
|
| Total value |
3.3 u |
0.7 u |
$40 |
Amount collected if all the tarts are sold
= 3 u x 1.1
= 3.3 u
Amount collected if all the shortbreads are sold
= 1 u x 0.7 u
= 0.7 u
Amount collected if all the tarts and shortbreads are sold
= 3.3 u + 0.7 u
= 4 u
4 u = 40
1 u = 40 ÷ 4 = 10
Total number of tarts
= 3 u
= 3 x 10
= 30
Answer(s): 30
